1. Field
The described technology relates generally to a thin film forming apparatus, and more particularly, it relates to an organic thin film forming apparatus for an organic light emitting diode (OLED) display.
2. Description of the Related Art
An organic light emitting diode (OLED) display includes two electrodes and an organic emission layer disposed between the two electrodes. Here, electrons injected from one electrode and holes injected from the other electrode are combined in the organic emission layer such that excitons are formed, and light is emitted by energy generated from the excitons.
An organic material should be vapor-deposited on a substrate in order to form, e.g., an organic emission layer. For example, the organic material is vapor-deposited by a vapor deposition source filled with an organic material and a thin film forming apparatus formed of a plurality of nozzles that spray (or vapor-deposit) the organic material heated in the vapor deposition source. The thin film forming apparatus can be changed to a linear vapor deposition type from a dotted vapor deposition source for increasing the size and reducing cost. A thin film forming apparatus formed of a linear vapor deposition source can simultaneously vapor-deposit the organic material in a linear direction so that the thickness uniformity of the organic material can be improved and the vapor-deposition speed of the organic material can be improved.
However, the organic emission layer or an electron transfer layer in the OLED display are formed by mixing a plurality of organic materials and vapor-depositing the mixture, and therefore a plurality of vapor deposition sources are used. In this case, since the plurality of vapor deposition sources are at different locations, a vapor deposition flux of an organic material sprayed from a nozzle of each vapor deposition source is created so that mixture uniformity of the mixed organic material may be deteriorated and a characteristic of the OLED display may be deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.